Heat exchanger



J1me 1967 K. v. EISBERG ETAL 3,326,279

HEAT EXCHANGER Filed March 21, 1966 2 mm l r um r mm P 3 ww 7 Ir r n 71 MI NM INVENTORS KEITH V EISBERG BY JOSEPH R. BOURNE.

wzzzw ATTORNEY.

United States Patent 0.

3,326,279 HEAT EXCHANGER Keith V. Eisberg, Camillus, and Joseph R. Bourne, Dewitt, N .Y., assignors to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed Mar. 21, 1966, Ser. No. 535,753 5 Claims. (Cl. 165-133) This invention relates to heat exchangers and, more particularly, to a heat exchanger for use in an absorption refrigeration system.

In heat exchangers, which function to bring two or more fluid mediums into heat exchange relation, the metal portions thereof are subject to corrosion and pitting when one of the fluid mediums is corrosive in nature. For example, the part supporting the several heat exchanger tubes, the tube sheet, is preferably metal, and the corrosion and pitting that attends the continuing exposure of the tube sheet to a fluid medium such as water with corrosive properties may loosen the heat exchanger tubes to cause leaking of the joint between the heat exchanger tubes and the tube sheet. Additionally, corrosion and pitting of the metal surfaces on the water side of the heat exchanger may roughen and undermine the mating gasket supporting surfaces thereof causing leaking and requiring resurfacing or replacement of the metal parts.

It is a principal object of the present invention to provide a new and improved arrangement for protecting the metal portions of a heat exchanger against corrosion and pitting.

It is a further object of the present invention to provide a heat exchanger incorporating a corrosion resistant elastomeric coating on metal parts which may be exposed to fluids corrosive in nature to prevent corrosion and pitting thereof.

It is a further object of the present invention to provide a tube type heat exchanger for use with an absorption refrigeration system wherein the walls of the tube support sheets which are exposed to condensing water are coated with an elastomeric corrosion resistant adhesive'having a protective gasket cover thereover.

This invention relates to a tube type heat exchanger comprising, in combination, means forming a chamber adapted to receive a relatively corrosive heat exchange medium, the chamber forming means including a metal tube support sheet forming one end of the chamber having tube receiving openings therethrough, a heat exchanger tube tightly and sealingly disposed within each of the tube support heet openings, the heat exchanger tubes opening into the chamber, a plate-like cover forming an opposite end of the chamber, and a hollow spacer with substantially planar end walls engaged between the tube sheet and the cover, the spacer defining the peripheral wall of the chamber; a corrosion resistant adhesive coating on the side of the tube sheet facing the chamber; a first gasket-type seal bonded to the tube sheet side by the adhesive coating to prevent the heat exchange medium from eroding the adhesive coating during operation of the heat exchanger; and a second gasket-type seal over the first seal to provide a fluid-tight join-t between the first seal and the engaging planar end wall of the spacer.

Other objects and advantages of the invention will be apparent from the ensuing description and drawing in which the figure i a sectional view illustrating the heat exchanger of the present invention.

Referring to the drawing, a heat exchanger of the type suitable for use in an absorption refrigeration system as the condenser section and/or absorber section thereof is there on shown. Heat exchanger 10 includes outer shell or enclosure 12 with plate-like tube support sheets 14 sealingly fixed to opposite ends thereof as by welding. Shell 12 and support sheets 14 cooperate to 3,3Z.6,Z 79 Patented June 20, 1967 define chamber 16. Inlet opening 18 in the upper wall of shell 12 communicates chamber 16 with a source of primary heat exchange medium to be condensed. Outlet opening 19 in the lower wall of shell 12 permits egress of condensed primary medium from chamber 16. Where, for example, heat exchanger 10 is used as the condenser section of an absorption refrigeration system, inlet opening 18 thereof communicates with the absorption system generator section while outlet opening 19 communicates with the evaporator section thereof.

Tube support sheets 14 each have a plurality of axially aligned openings 22 therethrough within which the terminal ends 26 of the heat exchanger tubes 25 are disposed. Heat exchanger tubes 25, which extend longitudinally through chamber 16, may comprise any suitable heat exchanger surface, for example finned section. Where the space between tube sheets 14 is relatively large, intermediate tube support sheets (not shown) each having tube receiving openings therethrough coaxial with openings 22 in tube sheets 14 may be provided to obviate sag of the heat exchanger tubes and maintain desired tube spacing.

Ends 26 of heat exchanger tubes 25 project slightly 'beyond the outer wall of tube support sheets 14. Gaskets 30, having openings therethrough to accommodate ends 26 of the heat exchanger tubes 25, are bonded to the outer side of each tube support sheet 14 by an adhesive 29, as will be more particularly explained hereinafter. Removable gaskets 32, having tube openings therethrough, overlay gaskets 30.

Spacer or separation plates 35 abut gaskets 32 adjacent the outer edge thereof. The dimensions and configuration of spacers 35 preferably conform to that of gaskets 30, 32 and spacers 35 encompass the cluster of tube ends 26 projecting from each tube support sheet 14. Gaskets 37 are positioned between the outer end of spacers 35 and the inside wall of cover plates 40. Cover plates 40 are clamped to support sheets 14 by suitable means, for example bolts 42.

Gaskets 30, 32, 37 are comprised of any suitable commercially available gasket material, such as cork, asbestos, neoprene, etc. Gasket 30 is preferably relatively hard while gaskets 32, 37 are relatively soft so that, on tightening of bolts 42, gasket 37 is compressed between cover plate 40 and the outer-most end of spacer 35, while gasket 32 is compressed between gasket 30 and the innermost end of spacer 35 thereby sealing compartments 45, 46.

The compartments 45, 46 formed by each cover platespacer assembly with the outer Wall 28 of the tube support sheet 14 communicate with one another through heat exchanger tubes 25. Compartment 45 is divided by partition 48 into inlet and outlet sections 49, 50, respectively. Opening 52 in inlet section 49 communicates with a suitable source of secondary heat exchange medium. Opening 54 in outlet section 50 permits exhaust of secondary heat exchange medium from heat e'xchanger 10.

Secondary heat exchange medium from inlet section 49 of compartment 45 passes through those heat exchanger tubes in communication therewith into compartment 46 and through the remaining heat exchanger tubes to outlet section 50 of compartment 45. Suitable bafliing (not shown) may be provided in compartment 46 to guide the flow of secondary heat exchange medium therein.

When heat exchanger 10 is employed as the condenser section, or absorber section, of an absorption refrigeration system, the secondary heat exchange medium is normally water which, depending upon the source, can be highly corrosive. Tube support sheets 14, which are usually metal, for example steel, may be corroded and pitted from contact with the water. Corrosion and pitting of sheets 14 circumjacent tube receiving openings 22 thereof may loosen heat exchanger tubes 25 breaking the normally fluid-tight joint between tube ends 26 and support sheet 14 and permitting seepage and leakage of primary heat exchange medium from chamber 16 into the water thereby reducing or destroying the efiiciency of heat exchanger 10. Additionally, the normally smooth gasket :bearing surfaces of support sheet 14. spacer 35, cover plate 40 and partition 48, may be eroded and roughened, destroying their effectiveness as a sealing surface and permitting leakage of the water from heat exchanger 10.

To prevent corrosion and pitting of tube support sheet 14 by the water or other medium in compartments 45, 46, the water sides 28 of each sheet 14 are coated with an elastomeric, corrosive resistant layer of adhesive material 29. The primary function of the adhesive layer 29 is to insulate and protect sides 28 of tube support sheets 14 from the corrosive effect of the water or other secondary heat exchange medium.

Gasket 30, which is tightly held over the layer of adhesive material 29 by the adhesive qualities of material 29 prevents erosion'of the adhesive layer 29 by the water of other secondary heat exchange medium during operation of heat exchanger 10. Gasket 32, placed over gasket '30, seals between gasket 30 and the inner-most wall of spacer 3'5. Gasket 37 covers and protects the inside wall of cover plate 40 and seals between cover plate 40 and the outer-most end of spacer 35.

Where desired, the inside wall of cover plate 40 may be coated with elastomeric bonding material 29 to protect cover plate 40 from corrosion and pitting and to retain gasket 37 thereon. Additionally, the inner wall of spacer 35 may be coated with corrosion inhibiting adhesive material 29.

While we have described a preferred embodiment of this invention, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

We claim:

'1. In a tube type heat exchanger, the combination of means forming a chamber adapted to receive a relatively corrosive heat exchange medium, said chamber forming means including a metal tube support sheet forming one end of said chamber having tube receiving openings therethrough, a heat exchanger tube tightly and sealingly disposed Within each of said tube support sheet openings, 4

said heat exchanger tubes opening into said chamber, a plate-like cover forming an opposite end of said chamber,

and a hollow spacer with substantially planar end walls engaged between said tube sheet and said cover, said spacer defining the periphery wall of said chamber; a corrosion resistant adhesive coating on the side of said tube sheet facing said chamber; a first gasket-type seal bonded to said tube sheet side by said adhesive coating to prevent said heat exchange medium from eroding said adhesive coating during operation of said heat exchanger; and a second gasket-type seal over said first seal to provide a fluid-tight joint between said first seal and the engaging planar end wall of said spacer.

2. A heat exchanger according to claim 1 including a third gasket-type seal between the side of said cover facing said chamber and the engaging planar end wall of said spacer to provide a fluid-tight joint between said spacer and said cover.

3. A heat exchanger according to claim 1 in which said adhesive coating is comprised of an elastomeric material.

4. A heat exchanger according to claim 3 in which said cover plate is metal, said adhesive coating being disposed on said cover plate side to seal said cover side against corrosion and tightly afiix said third seal to said cover.

5. A heat exchanger according to claim 1 in which said first seal is comprised of a relatively hard gasket type material while said second seal is comprised of a relatively soft gasket-type material.

References Cited UNITED STATES PATENTS 1,120,121 12/1914 Behringer 165-158 2,075,511 3/1937 Baufre 165-133 X 2,240,537 5/1941 Young 165-178 X 2,303,416 12/1942 Woods 165-178 X 2,821,369 '1/1958 Hilliard 165-159 2,879,116 3/1959 Goetze 165-133 3,001,766 9/1961 Laist 165-134 3,186,924 6/1965 Williamson 202-173 FOREIGN PATENTS 558,124 12/ 1943 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner, 

1. IN A TUBE TYPE HEAT EXCHANGER, THE COMBINATION OF MEANS FORMING A CHAMBER ADAPTED TO RECEIVE A RELATIVELY CORROSIVE HEAT EXCHANGE MEDIUM, SAID CHAMBER FORMING MEANS INCLUDING A METAL TUBE SUPPORT SHEET FORMING ONE END OF SAID CHAMBER HAVING TUBE RECEIVING OPENINGS THERETHROUGH, A HEAT EXCHANGER TUBE TIGHTLY AND SEALINGLY DISPOSED WITHIN EACH OF SAID TUBE SUPPORT SHEET OPENINGS, SAID HEAT EXCHANGER TUBES OPENING INTO SAID CHAMBER, A PLATE-LIKE COVER FORMING AN OPPOSITE END OF SAID CHAMBER, AND A HOLLOW SPACER WITH SUBSTANTIALLY PLANAR END WALLS ENGAGED BETWEEN SAID TUBE SHEET AND SAID COVER, SAID SPACER DEFINING THE PERIPHERY WALL OF SAID CHAMBER; A CORROSION RESISTANT ADHESIVE COATING ON THE SIDE OF SAID TUBE SHEET FACING SAID CHAMBER; A FIRST GASKET-TYPE SEAL BONDED TO SAID TUBE SHEET SIDE BY SAID ADHESIVE COATING TO PREVENT SEAT HEAT EXCHANGE MEDIUM FROM ERODING SAID ADHESIVE COATING DURING OPERATION OF SAID HEAT EXCHANGER; AND A SECOND GASKET-TYPE SEAL OVER SAID FIRST SEAL TO PROVIDE A FLUID-TIGHT JOINT BETWEEN SAID FIRST SEAL AND THE ENGAGING PLANAR END WALL OF SAID SPACER. 